1. Field of the Invention
The present invention relates to the field of clinical tests, more particularly to a method for accurately and rapidly detecting an antibody against a granulocyte antigen (granulocyte antibody) in serum which is considered as one of the causes of granulopenia (neutropenia) and transfusion side effect, and a panel cell used for said method.
2. Background Art
In recent years, diseases in which a granulocyte (neutrophil) antigen is involved have been reported in a variety of clinical situations. Diseases in which an isoantibody is involved include isoimmune neonatal neutropenia, isoimmune neutropenia after hematopoietic stem cell transplantation, granulocyte transfusion refractoriness, transfusion-related acute lung injury, anhemolytic transfusion side effect, and the like. Also, diseases in which autoantibody is involved include primary autoimmune neutropenia, secondary autoimmune neutropenia, and the like. In these diseases, an anti-human leukocyte antigen (HLA) antibody may be observed concomitantly with the granulocyte antibody, and thus there is a need for an examination method for accurately and rapidly discriminating and identifying these antibodies.
The examination of granulocyte antibody usually employs: a method for detecting granulocyte antibody by flow cytometry using blood granulocyte as a panel cell (cell for discrimination) (GIFT); a method by using the agglutination of granulocytes as an index (GAT); a method for reacting serum and a mouse monoclonal antibody with granulocyte to determine a resulting antigen-antibody complex (MAIGA); a method by using a plate having granulocyte (or granulocyte extraction antigen) immobilized thereon and reacting the plate with a sample to judge the agglutination of the bonded antibody and the anti-human IgG sensitive blood cell (or sensitive beads) as an index (MPHA); a method in which the detection step involved in MPHA is carried out by using a labeled antibody (EIA), and the like. In the method by using human granulocyte, blood is taken from a blood donor and granulocyte is isolated from the blood thus obtained for every examination, so that the reactivities with the granulocyte antibodies vary individually. Also, in the method which uses the human granulocyte as a panel cell, high levels of backgrounds are observed in measurement results of flow cytometry and the like, and the levels of the backgrounds vary depending on individual granulocytes, so that it is difficult to obtain accurate test results stably. Thus, there is a need for the development of a panel cell strain for detecting granulocyte antibody which allows obtaining accurate test results stably.
Hitherto, researchers in many countries including Japan have tried to develop a panel cell strain for detecting the granulocyte antibody. J. Bux et al. in Justus Liebig University have prepared a panel cell strain which expresses granulocyte antigens HNA-1a, HNA-1b and HNA-SH by transfecting genes coding for these antigens into CHO cells (Chinese hamster ovary cell line) (Blood, vol. 93, No. 1, 1999: pp. 357-362). Also, Miyazaki et al. in Hokkaido Red Cross Blood Center have prepared a CHO cell and a COS-7 cell (African green monkey kidney cell line) which express HNA-1a and HNA-1b (Japanese Journal of Transfusion Medicine 50, 2, 2004: pp 297) as well as a 293T cell (Human kidney cell line) expressing HNA-2a (Japanese Journal of Transfusion Medicine 51, 2, 2005: pp 188).